A major users group of six enzymologists and molecular biologists in the Department of Chemistry and Biochemistry of the University of Maryland at College Park seeks funding for an autoradiograph imager; the major users group is composed of Drs. Armstrong, Dunaway-Mariano, Gerlt (P.I.), Hansen, Julin, and Kozarich. This imager will be used in lieu of traditional autoradiographic methods for quantitation of DNA damage by various antibiotics and enzymes, quantitative Southern and Northern blot analyses, and DNA sequence analyses of mutant genes, some of which are significantly GC rich. The imager decreases the time required to obtain data describing the distribution of radioactivity on gels and filters due to the enhanced sensitivity of its phosphor screens as compared to X-ray film. The software provided with the imager also allows quantitative treatment and comparisons of data on different regions of gels and filters. The hard copy of the gel or filter which is provided by a laser printer is suitable for publication and also will facilitate the accurate reading of DNA sequencing gels.